The Dell XPS 12 is one of the first of the new Windows 8 convertibles (doing double duty as an ultrabook and a tablet) to hit the market. It sports a beautiful 12.5-in. screen, suitable power under the hood and a number of clever design touches. If you have a need for this type of a double-duty device, you'll find it will do well -- with some caveats.

The XPS features standard hardware for an ultrabook. The unit I tested has an Intel Core i5-3427 running at 1.7GHz and has 4GB of RAM, along with a 128GB SSD; it lists at the Dell site for $1,199.99. Other configurations are available with 8GB RAM, a Core i7 processor and/or a 256GB SSD hard disk. The top-of-the-line model, which has all these features, sells for $1,699.99.

What sets the XPS 12 apart from other ultrabooks is its "convertible" feature -- the ability to work both as a tablet and as a traditional notebook. It accomplishes this with a very clever and well-executed design. The screen is set in a frame and flips 180 degrees on a hinge so that it can face away from the keyboard. Fold the screen down onto the body of the keyboard, and you're left with a tablet. The design is simple, clean, and downright nifty.

Dell XPS 12

The screen itself is a real standout and may be the best part of the XPS 12. Protected by Gorilla Glass, it sports a 1920 x 1080 resolution and is exceptionally bright and vivid, excelling both as a traditional screen and a touchscreen.

Performance was snappy, and I experienced no delays launching and running apps, watching videos and playing music. The speakers are adequate, with plenty of volume.

The system comes with basic connections: two USB 3.0 ports (one with PowerShare, which lets you charge USB-connected devices even when the XPS is powered off or sleeping), a Mini DisplayPort for connecting to an external display and a headphone jack. There's no Ethernet jack nor is there a slot for an SD card.

For those who want to check the battery power reserves, there's a nice feature: Press a small button on the right side of the system, and a series of tiny lights illuminates letting you know how much power is left.

As an ultrabook, though, the XPS is heavy at 3.35 lb. A MacBook Air with a 13.3-in. screen, for example, weighs nearly a half a pound less at 2.96 lb., and the 13.3-in. Asus Zenbook UX31A Touch weighs in at 3.08 lb., despite its larger screen size.

Keyboard and trackpad

When you use the XPS12 as a notebook, you'll spend plenty of time with its keyboard and trackpad, and you'll find them a mixed bag. The keyboard feels slightly cramped, and those with large hands may take some time getting used to it. But the keys spring back as you touch them, making the keyboard easy to type on. The keys are backlit, so it's easy to use in low light. All in all, it's a solid keyboard for an ultrabook.

I ran into problems with the trackpad, though. When when I used it to scroll sideways, the cursor tended to cause herky-jerky motions. I also sometimes had problems getting the Windows 8 Charms bar to appear when I moved the cursor to the upper-right corner of the screen. And several times, the Charms bar appeared when I moved the mouse cursor to the center of the Start screen -- for no apparent reason. I also initially found that I had to double-tap harder than expected for it to register with the device; once I got used to that, though, things improved.

The trackpad worked better when using multitouch Windows 8 gestures. Zooming in and out was smooth, and most Windows 8 swiping gestures worked similarly well.

XPS 12 as a tablet

With a big 12.5-in. screen, vivid display, quick response to touches and swipes, and smooth scrolling and zooming, the XPS seems perfectly suited for tablet tasks -- or at least it does for a minute or two. Then reality sets in.

DellStarting price: $1,199.99Pros: Beautiful, vivid screen; innovative design; good keyboardCons: Problems with trackpad; a bit heavy for an ultrabook and too heavy for a tablet

At 3.35 lb., the XPS very quickly becomes far too heavy to be useful -- when I tried just holding it and working, or watching a video, I soon felt tired and uncomfortable. And when I put it in my lap, it got hot relatively quickly.